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Metallurgy
Introduction The time is around 9000 B.C.E. A Stone Age hunter picks his way through a riverbed looking for flint suitable for tools and weapons. His eye is caught by the sight of a rock that glimmers "far, as from the moon" as the Greek poet Homer would put it over 8000 years later. It certainly is not flint, but it is interesting, so he takes it home to see what he can do with it. The rock bends, but does not break or chip under the blows of his hammer stone. Our hunter can shape it into some little trinket such as a pin that will probably make quite a stir with his friends and family and be a valuable item in trade. In such a modest way was metallurgy born. Today it would be hard to imagine our civilization without metals. After all, just about every manufactured object we have either has metal in it or was made by metal machines and transported on ships, trains, or trucks made of metal. Without metals, we would literally be living back in the Stone Age. The development of metallurgy was a long, and sometimes devious process that involved five basic steps. #Identifying and discovering its usefulness. There is little in nature to suggest the existence of metals or their usefulness. Our Stone Age hunter managed to find a small copper ingot. Unfortunately, metals rarely occur in such a pure state. Instead, we find them mixed with other minerals in rocks called ore. Ores usually do not present the appearance of anything resembling metal, so the question arises as to how people discovered them. As with so many discoveries, it was probably by accident. One likely scenario is that potters would put some minerals containing copper on the pottery to give it a glaze when fired. The kiln's heat would separate the copper from the rest of the glaze, leaving little beads of copper lying around. Further experiments would lead to the realization that other rocks were also ores containing copper. #Locating metals in quantity. Our potters, wanting larger amounts of the copper ore, find there is little to be found lying on the surface. As a result, they start digging near the surface deposits and find more copper ore in the ground or the sides of hills. Eventually, they will find that copper mixes with different minerals to produce a variety of ores rarely resembling each other. #Mining the ores. Now that they know where the ores are, they have to mine them. This is one of the more unpleasant aspects of ancient metallurgy. In fact, work in the mines will become the most brutal and demoralizing job in the ancient world, being reserved for slaves and condemned criminals. It is unfortunate that the glories of ancient civilizations and the modern civilizations later built upon them would have to depend so much on the intense suffering of slaves whose life expectancy in many of the mines was no more than six months to a year. #Smelting the metal. Smelting means heating an ore to a high enough temperature that the metal will separate from the rest of the ore, known as slag. As stated above, the first incidence of smelting was probably by accident in a pottery kiln. Over the years, metal smiths would come up with various innovations that created hotter fires and the ability to smelt stronger metals such as bronze and iron. Bellows were invented for blowing air into the fire. The kiln was enclosed to trap heat. And charcoal, partially burnt wood that burns at a higher temperature than regular wood, was developed as a fuel. #Shaping the metal into something useful. There were two basic methods for doing this. One method was to pour the molten metal into molds. The other was to pound the metal into the desired shape, such as a sword. The Ages of Metals There were three ages of metals in the ancient world, each named after the current dominant metal that was used for constructing weapons and tools in that time. They are the Copper Age (c. 4000-3000 BCE), The Bronze Age (c. 3000-1000 BCE), and finally, the Iron Age (c. 1000 BCE to the present). They went in order from the easiest to smelt, which was copper, to the hardest, iron. The Copper Age had very limited use of copper, ironically, because it is soft and not very useful for many tools and was also expensive for the average person, so, most people were still living in the Stone Age. The Bronze Age, during which such civilizations such as Mesopotamia, Egypt, and Minoan Crete reach their zenith, saw new metals come into their own in the near east. Bronze is an alloy of copper and another certain metal, which is usually tin, and is much stronger than either of its sub-metals. The first bronze used, however, was an alloy of copper and arsenic and, unfortunately, was deadly because of the fumes the arsenic gave off and thus, was quite uncommon for blacksmiths to use the particular alloy. This did, however, give them the idea of mixing copper with different metals to eventually develop a bronze of copper mixed with a small amount of tin, usually 1-4% of the total mixture. Tin was also scarce, unforunately, and so had to be sought out in Europe and Central Asia. This was vital because they had to build trade routes for importing and exporting tin to the different land masses and led to the spread of power, culture, people, ideas, etc. Although, a setback of bronze was that it was expensive, and so was only available to a limited amount of people, and as a result, many Bronze Age civilizations were highly aristocratic societies of narrow classes of nobles and priests ruling over masses of peasants still using stone tools and items.